The present invention relates generally to fiber-based ceramic substrates useful for insulation, filtration and/or high temperature chemical reaction processing, such as a catalytic host. The invention more particularly relates to an aluminosilicate fiber-based ceramic substrate and methods for producing the same.
Fiber-based ceramic substrates are commonly used for high temperature processes, such as exhaust filtration, insulation, and as a catalytic host in chemical reactors. Fiber-based ceramic substrates provide high operating temperature capabilities, with high strength and chemical inertness. Rigid structures can be formed that maintain structural integrity at extremely high temperatures in order to meet the processing requirements of the intended application. The ceramic fiber forming the basis for the substrate material composition can be fabricated from a number of materials in a variety of processes. For example, ceramic materials can be drawn into a fiber from a sol-gel, or melt-spun into fibers.
Fiber-based ceramic substrates exhibiting high strength with chemical and thermal stability are typically fabricated with high performance, high temperature, and thus, expensive ceramic fibers. For example, polycrystalline mullite fiber is highly stable, with mechanical integrity at temperatures in excess of 1700° C. These high performance materials require significantly more cost to manufacture due to the processes used to form the material into a fiber, and due to the purity and grade of the raw materials used to formulate the fibers. Fiber-based substrates from low cost materials such as vitreous aluminosilicate have not been associated with high performance, since the material de-vitrifies and crystallizes into a lower strength, and potentially hazardous, form when exposed to elevated operating temperatures.
Accordingly, there is a need for a fiber-based ceramic substrate that can be fabricated using low cost fibers that provide superior chemical and thermal resistance.